The proposed research is intended to produce methods for the positive identification of animals with encephalitozoonosis which will result in eradication of this serious disease of experimental animals. Mammalian encephalitozoon can now be isolated and propagated in tissue culture. These methods will be used to produce large amounts of pure organisms and their antigens. Serological diagnostic methods for the detection of infected animals will be improved and developed. Mammalian and invertebrate microsporida will be compared morphologically and biologically to ascertain the number of different species infecting mammals. Modes of transmission of the parasite will be studied. Attempts will be made to develop methods to diagnose human microsporidosis.